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3124590 
Journal Article 
Location of TEMPO derivatives in micelles: subtle effect of the probe orientation 
Aliaga, C; Bravo-Moraga, F; Gonzalez-Nilo, D; Marquez, S; Luehr, S; Mena, G; Caroli Rezende, M 
2016 
Yes 
Food Chemistry
ISSN: 0308-8146
EISSN: 1873-7072 
ELSEVIER SCI LTD 
OXFORD 
192 
395-401 
English 
26304365 
WOS:000362304500053 
Partition coefficients for six 4-substituted derivatives of the 2,2,6,6-tetramethylpiperidine-N-oxyl (TEMPO) derivatives in aqueous solutions of reduced Triton X-100 (RTX-100) were determined by measurements of the probe EPR g-factor and of the fluorescence quenching of pyrene by the radical in the micelle. The partition constant attained a maximum value and then decreased with increasing probe hydrophobicity. Simulation of the probes inside the micelle showed that this trend could be rationalized by a change in the orientation of the 4-substituted TEMPO derivatives with the increasing substituent chain-length. The use of the EPR g-factor for the determination of partition constants of radicals in micellar systems was thus validated as a reliable and sensitive method, capable of describing the probe orientation in its microenvironment. 
Partition constants; 4-AcyloxyTEMPO; Reduced Triton X-100 micelle; EPR g-factor; Molecular dynamics simulation